Peters



UNITED STATES PATENT GEEICE.

JOHN S. BROWN, OF WASHINGTON, DISTRICT OF COLUMBIA.

MAGNETO-ELECTRIC SIGNALING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 238,212, dated March 1,1881. Application filed June 17, 1880. (N0 model.)

To all whom it may concern:

Be it known that 1, JOHN S. BROWN, of Washington,in the county ofWashington and District of Columbia, have invented a new and ImprovedMagnetic Telegraph; and I do hereby declare thatthe following is a fulland exact description thereof, reference being had to the accompanyingdrawings, making part of this specification.

In the drawings, Figure l is a top view of my improvedtelegraph-instrument, and Fig. 2 a central vertical section thereof in aplane cutting from front to back.

Like letters designate corresponding parts in both figures.

The purpose of my improvement is to dispense with galvanic batteries intelegraphing, and thereby to save a large expense in operating, and alsoto simplify and lessen the cost of telegraph-instruments. Anotherpurpose effected is a greater distinctiveness in the signals produced,thereby conducing to facility and certainty in reading messages.

My invention consists in the method and means by which a permanentmagnet is employed as the sole generator of the electric current wherebythe signals are transmitted, substantially as hereinafter specified.

With this invention sound-symbols are employed to indicate the languageconveyed, using the Morse time-alphabet or any other on the sameprinciple. Since the magnetic telephone transmitting articulate speechis dependent on the vibrations produced by the voice acting on thediaphragm-armature of a magnet, the force of which is comparativelysmall, the distance to which intelligence can be conveyed thereby is notgreat. Besides, the publicity necessarily given in transmitting messagesby this means is incompatible with the confidential nature oftelegraphic as well as other correspondence; but by means of myinvention the force capable of being given to the armature-vibrations isalmost unlimited, and the distance to which the sounds thereby producedcan be conveyed by the simple magneto-electro current is correspondentlygreat.

For the transmitter I combine with a permanent magnet and thecurrentgenerating coil surrounding the same a vibratory reed-armatureand a hammer-key to communicate the pitch or tone of its own, asdistinguished from a diaphragm-armature, which, being confined at itsopposite edges, has no essential tone of its own, but responds to anytone, sound, or

noise that the electric Waves acting on the magnet may produce; and by ahammerkey Imean a mechanical strikeracting against the reed-armature andactuated by hand.

For the receiver I employ a diaphragm-armature with a magnet and ,coil,to respond instantly to the making and ceasing of the current waves orvibrations. It may be a separate instrument-a simple receiving-telephonebut I prefer to combine it in one instrument with the transmitter,employing one permanent magnet with the reed'armature and hammerkey atone end or pole and the diaphragmarmature at the other end or polethereof; and I use either one coil or two branch circuitcoils around thetwo poles of the magnet.

I will now describe specifically the combined transmitting and receivingtelegraph-instrument represented in the accompanying drawings.

Upon a base, A, and within a suitable case, B, a permanent magnet, O, ismounted. Itmay be a simple straight magnet, arranged vertically, asshown, or it may be a compound magnet of any required power andconvenient form, and arranged to best suit the operator. Around thelower end of the magnet is a current-generating coil, D, and around theupper end is a coil, E. The two coils are to be in the line-circuit, butare preferably in separate branch circuits, for the special purposehereinafter specified.

Beneath the lower pole of the magnet is socured at reed-armature, G,fixed at a convenient point, a, to the base or case, and arranged at theproper distance from the pole, that being the least that will allow theamplest vibrations of the armature without coming in contact with themagnet.

Upon the base is mounted, on a pivot, b, a hammer-key, H, the hammer cof which is caused, by the depression of the outer end, d,

of the key, to strike upward against the reedtinctive mark.

armature. nearly pointed, or, better,with an edge extending transverselyto the armature. The hammer is made to strike the armature at a nodalpoint or line, so that not only will the armature give a clearer, fullertone When the hammer strikes it momentarilyas for producing the shortsignals in the Morse alphabetbut when the hammer is held against thearmatureas for producing the long signals of the said alphabet-aharmonic is produced, and the vibrations of the armature continue nearlyas ample and forcible as those produced by a momentary impulse. Thenodal point preferred is either onequarter, as shown in the drawings, orone-third of the distance from the fixed end of the armature, althoughonehalf ofthe distance might be the arrangement; but though the octaveharmonic is clearer and fuller than any other, the common multiple withthe foundation tone being the smallest, yet the greater length of thefree end of the armature, when the hammer strikes only onefourth orone-third of the distance from its fixed end, produces more amplevibrations, which can be transmitted to a greater distance. A specialadvantage of this arrangement of the hammer to strike a nodal line ofthe armature, aside from considerations relating to the force andclearness of the vibrations and the simplicityof theconstruction oftheinstrument due thereto, consists in the supeiiordistinctiveness ofthe prolonged sounds of the alphabet, they being in reality differentintone from the short sounds, thereby rendering the signals much morereadily distinguished, the element of pitch being added to that of timeas a dis- The circuit of the current-generating coil D is arranged toinclude both the hammer and the reed-armature, so that when the hammerisdown the circuit is broken, and when the hammer strikes the armaturethecircuit is thereby closed. The great advantage of this constructionlies in -this, that at the moment when the hammer is separated from thearmature the vibrations of the armature instantly cease to betransmitted alongtheline, while the vibrations themselves continue,whereby more prompt and complete cessation of the sounds is effected atthe receiver; but

' since the vibrations of the armature continue the hammer keeps up amore forcible vibration thereof than itcouldif the armature should cometo rest between the strokes of the hammer. Another advantage is, thatthe currentgenerating coils are all shunted out of theline- The hammer cis properly madel circuit except that of the instrument transmitting themessage, thereby avoiding the resistance which would arise from thesecoils.

The diaphragm-armature I for the receiver is arranged as in ordinarytelephones, and l needs no further specification. The magnet is adjustedin relation to this armature by a suitable adjusting device, mostconveniently arranged near the middle of the magnet, as represented. Theconstruction shown consists of a transverse slightly-inclined hole, f,through 1 the magnet, in which moves a ball or disk, 9, just fitting thehole, and mounted on a screwshaft, h, arranged at right angles to themagnet, the screw t' causing the ball or disk to travel forward orbackward in the hole, thereby raising or lowering the magnet. Theadjustment of the magnet to the upper armature will not ordinarilydisturb the relative positions of the magnet and the lower armature,since the adjustment of the latter is not required to be so exact anddelicate as at the receiving-armature; but the fixed holder of thereed-armature or the armature alone may be made adjustable in anyconvenient way.

What I claim as my invention, and desire to secure by Letters Patent, is

1. In a transmitting-telegraph, the combination of apermanent magnet,(J, current-generatingcoilD, reed-armature G, and hammer-key H,substantially as and for the purpose herein specified.

2. The combination of a permanent magnet, U, current-generatingcoilD,reed-armature G, and ham mer-key H, arranged to strike the saidarmature on a nodal point orline, substantially as and for the purposeherein specified.

3. The current-generating circuit, arranged to include the key-hammerand the reed-armature, so that it is closed when the hammer comes incontact with the armature, and is broken when the hammer recedestherefrom,

substantially as and for the purpose herein specified. 1 n

4. The combination, in one telegraph-instrument, of a permanent magnet,O, current-generatin g coil D, current-receivin g coil E, reedarmatureG, hammer-key H, and diaphragmarmature I, substantially as and for thepur- 1 pose herein specified.

The foregoing specification signed by me this 9th day of June, 1880.

JOHN S. BROWN. "Witnesses:

JOHN T. ARMS," GEO. I. HILL.

